The present invention relates to an improved insulated furnace roller, and in particular to such rollers employed in high temperature furnaces for heating or reheating metallic workpieces incident to their being processed, for example, by rolling.
U.S. Pat. Nos. 3,860,387 and 4,991,276, as well as U.K. Patent No. 429,626 relate to rollers for conveying workpieces, such as metal slabs, plates and strips in such furnaces. The disclosed rollers comprise inner arbors for supporting outer tubes, sleeves or tires which support the horizontally disposed workpieces as they pass through the furnace. The arbors of these patents are internally air or water cooled to structurally protect the arbors from the intense heat that may in the case of the U.S. patents be in excess of 2000.degree. F. To further protect the arbors from being overheated, which would cause their structural failure, and to prevent the cooling effect of the arbors from adversely affecting the ability of the furnace to heat the workpieces to the desired temperature, insulation is provided for the rollers disclosed in the three patents between the arbors and the tubes, sleeves or tires.
To a great extent the success of past roller designs to operate over a long period of time in the environment involved were directly dependent on the ability of the insulation scheme employed to effectively insulate the rollers in carrying out the above two objectives. Past designs have repeatedly failed to do this due to the nature and structure of the insulation used and the manner and technic of applying the insulation to the rollers. Adding to the problem is the fact that the roller are caused to deflect under the weight of the workpiece. The past failures has revealed that what is needed is an insulation scheme that will bring together the proper types and structures of insulations and the manner and technic of applying the insulations to allow the rollers to operate in the severe conditions and roller deflection without the insulations quickly deteriorating and/or becoming detached from the rollers.